In falconry In falconry, casting involves giving a hawk roughage, which is regurgitated later to purge and cleanse its crop. Hawks in the wild will produce castings of their own accord, in the form of small pellets of fur, feathers, and other indigestible material, regurgitated hours after it has eaten. Of the roughage used for falcons in captivity, there are two kinds: plumage, and cotton; the latter of which is generally in pellets about the size of hazelnuts, made of soft fine cotton, and conveyed into the hawk's gorge after supper. In the morning, the hawk will have cast them out, at which time they should be examined for color and condition to determine the state of the hawk's body. If they are cast out round, white, without stench, nor very moist, then the hawk is healthy; if otherwise, particularly black, green, slimy, or the like, the hawk is ill. The casting of plumage is examined in the same manner. The yellow down feathers of day-old rooster chicks, which are a common diet among hawks in captivity, can be enough to induce casting. However, rabbit fur and feathers from game birds are better suited for this purpose. Casting will occur at the same time daily, provided that hawks are flown at the same time daily. Hawks in captivity are usually weighed immediately before being flown. If they were fed roughage the previous day, they should cast it out before being weighed, to avoid an inaccurate measurement. Casting is a necessary part of a hawk's survival. Not only does it clear out the crop, but the roughage that is regurgitated cleans bacteria from the walls of the crop. If hawks in captivity are not provided with this necessary roughage, and instead are simply fed meat, they will become seriously ill and unreleasable into the wild. References External links Owls & Owl Pellets Bird feeding